thomas ascroft walker



(No Modem J. `s T; A. su E. R. WALKER.

AIR VALVE. u I 10.289,192. `IPM@.lfltd NOY.- .27?,1383'4 N. Peleas Pmwwnngmpnu, wnmngnm n. c.

l' UNITED STATES jF PATENT Onrracn.

ROBERT WALKER, OF WIGAN, COUNTY OF LANCASTER, ENGLAND.

'Al R-VALVE.

SPECIFICATION forming part of Letters Patent No. 289,192, dated November 2'?, 1883. Application tiled .Tazuary 13. 1883. (No model.) Patented in England November 28. 1877, No. 4,488.

.T @ZZ whom t may concer/1,.-

Be it known that we, JOHN SoARisBnrcK WALKER, THoMAs Ascnorr VALKER, and EDWIN ROBERT NVALKER, all of Wigan,in the county of Lancaster, in the Kingdom of x England, have invented certain new and useful Improvements in Air-Valves, (for a part of y vention is designed.

which we have received Letters Patent l in England, dated November 28, 187 7, No. 4,488,)

of which the following is a clear and correct specification.

In the working of valves for compressing or exhausting air and other gaseous iiuids it is found` that the valves are apt to dance or fiap while the air is passing through the same, so preventing them working safely at any but a low velocity. Air, too', being such a very compressible material,` great waste occurs by air collecting in the parts of blowing-engines and airpumps and re-expanding at each stroke.

It is to overcome these evils that this our in In blowing-engines the parts are either placed on the sides of the cylinders or in their ends. WV e have, therefore, in our drawings shown two variations, so as to show the application of our invention both to the cylinder-covers and their sides. In some blowing-engines, indeed, the valves are on `the cylinder-cover, at the back and on the side of the cylinder at the front end.

. Referring to thedrawings, Figure lis apart plan, andFig. 2 a section of valve apparatus on a cover of a horizontal blowing-engine, the section being taken on Vthe line m Figi; Fig. 3, partial elevation of same.

.y The drawings illustrate our improvement embodied in valves applied to a cylindcrhead.

In the various figures, Arepresents the airadmission valve; B, the air-discharge valve; C, the stuflingfbox, through which the pistonrod will pass, and D the` cylinder-cover and cylinder. The air outlet or discharge valve B is hinged at one edge to the cylinder-head insuch manner as to swing outward, its inner surface being made in such form as to enter and nearly fill the port'or opening in order to reduce as much as possible the dead-air space. The closing -of the valve B isfeffected bythe pressure of a plunger or thimble, E, mounted in a tubular guide and depressed by means of a spiral spring, G The spring G bears at its upper end against the vertically-movable plate H, which is in turn depressed bythe second spiral spring, G', which is preferably compressed by means of a head or plate on the lower end of an adjusting-screw, I, allthese parts being mounted in the guide whichre ceives the plunger E. The spring G is to be weaker than the spring G, and is usually shorter in length. The spring Gf tends to relieve or equalize any sudden shock, and the spring G to act as a buffer to cushion the blow strongly at the end, the two springs serving jointly to give a smoothness and ease of action not otherwise attainable. If preferred, the springs G may be replaced by a spring or core composed of india-rubberg ,y Referring next to the inlet-valve A, it will be seen that it is hinged at one edge of the cylinder-headin such manner as to swing inward, and that, when closed, its inner surface is ilush, or practically iiush, with the inner surface of the head. The closing of the valve is effected by means of a link, J, attached to its outer side and pivoted at its opposite end to a plunger or piston, K, arranged to work inan `inclosing chamber or cylinder. To this `piston a rod or spindle, M, is secured and extended upward through guide-bars N, which are se cured rigidly in position by means of connecting-posts at their ends, as shown in Figs. 2 and 3. The upper end of the spindleMpasses between two friction-blocks, S and S", of castiron or other suitable material, mounted in the top of the frame N, and acted upon byascrew, Z, by means of` which they maybe caused to exert more or less friction upon the spindle, so as to retard its end motion, and thus limit the speed of the valve A.

In order to give the friction-blocksS and S a yielding pressure upon the spindle M, I prefer to introduce a rubber block or spring, L, between one of said parts and the inner end of the pressurescrew Z, as plainly represented in Fig. 2.

For the purpose of effecting the upward movement of the spindle Mto close the valve AI mount around said spindle a spiral spring, O, the upper end of which bears beneath a thumb-nut, I), screwed upon a threaded portion of the spindle. By turning this nut upward and downward the tension of the spring IOO may be increased or diminished, as circumstances may require. A jam-nut, I, applied immediately above the nut I), serves as a means of locking the same securely in position, so that it may not be jarred out of adj ustment.

For the purposeol cushioning or checking the closing action ol' the valve A and relieving the parts from shocks, I provide one of the crossba-rs ofthe frame N,in its under side,with a rubber spring or buffer, M, encircling the valvespindle M, and mou nt upon said spindle avertically-adjustable nut, T, designed to encounter the rubber buffer shortly before the valve reaches its seat. A companion nut serves as a check by which to prevent the nut T from working out of position.

For the purpose of relieving the construction from shock when the valve opens suddenly or violently, so as to severely compress the spring O, I sustain the lower end of said spring upon a collar or washer, R, which isin turn sustained by a rubber spring or buffer, Q, mounted ontop of one of the cross-bars of the frame N, as plainly represented in Figs. 2 and 3.

From the foregoing description it will be obscrved'that there is in connection with the inlet-valve A a spindle and friction-blocks to retard its motion, a spiral. spring, O, to effect its closing action, a cushion, Q, to relieve the closing-spring from strain as the valve opens, and a buffer, Q, to prevent the noise and shock at the instant that 'the valve completes its closing action. The necessity for the employment of the spindle and friction devices, as well as the buffers Q and Q', arises from the fact that in rapidly-running engines no spring vwhich can be rigidly applied will prevent the tendency of the valve to dance or chatter. The friction devices avoid this difficulty, for the reason that the force required to vibrate the valve after it is open is much less than that required to operate the valve, and that consequently the friction, which is pow- 'erless to prevent the opening ofthe valve, is

found quite strong enough to prevent the chattering action. By employing both the metallic spring O and the india-rubber buffer Q we obtain a quick action of the valve, combined with a rapid buffering action at the iinish of its movement, the spring and buffer combined giving a smoothness of action unobtainable with the single spring of great movement. For the same reasons we prefer to have the two springs of the outlet-valve B-one of india-rubber or stiffmetal, with little play, to act in the last instant, the other of steel, to govern the greater motion of the valve. India rubber washers inserted between the springs G and G may be employed for this purpose. These washers, if arranged to bear at the periphery against the guides, would have an action similar to that of the frictionblock S in the inlet-valve; but their use is not advised, except in engines running at very high speeds.

NVe claim as our invention- 1. In an air pump or engine, a valve, combined with a closing-spring and a friction device, substantially as shown, to prevent the valve from chattering.

2. In combination with the air-Controlling valve, the spring O, the block K, connected therewith, the spindle M, friction-block S, and compressing device Z, whereby a varying de gree of friction may be applied to limit the closing action of the valve.

3. The combination of the valve A, link J, spindle M, the closing-spring O, and an ad justable friction device acting upon the spindle, substantially as shown.

4:. The combination of the spindle M and spring O with the regulating device I?, bearings R, and rubber buffer Q, for the purposes described.

5. The combination of the spindle M, valve A, nuts T, and rubber ring Q on the frame, to break the force of the shock of the valve in closing and cushion strongly at the end of its movement to prevent noise.

6. The combination of the valveB, the plates E and II, and the two springs G and G.V

7. In combination with a rapidly-working valve, A, a spring, O, a friction device, S, to prevent dancing, and a cushioning device, Q Q', for cushioning strongly at the end of the stroke.

S. In combination with the Valve A and its closing-spring O, the adjustable friction device acting upon the spindle, and means, substantially as described, for adjusting the tension of the closing-spring, whereby the force of the closing-spring and the degree of friction opposed to the closing action may be varied independently as required.

9. In combination with the valve A and its spindle M, the spring O, the stationary frame N, and the cushions Q Q.

l0. In combination with the valve B, the long spring G, the superposed spring G, shorter in rlength but of greater strength than the iirst-nanied spring, and means I for varying the tension of the springs, substantially as described.

JOHN SCARISBRIOK WALKER. THOMAS ASOROFT WALKER. EDWIN ROBERT VALKER. IVitnesses to the signature of John Scarisl brick Walker:

THOMAS RENsHAw, I-IoRaTro BERLEY.

w'itnesses to the signatures of Thomas Ascroft Walker and Edwin Robert V-alker:

Josnrrr MURPHY, JOHN MANsHEAD.

ICO

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